Inventions disclosed herein relate to stimulation of hydrocarbon wells using diverters and evaluating and optimizing the efficiency of such stimulation. Other inventions also relate to the field of fluid flow diversion by use of mechanical blocking agents, such as degradable, solid-particle diverting agents. One particular example of products in this field is Weatherford International's TBLOCKSURE® product line. At the time of this filing, TBLOCKSURE® is a trade name given to a suite of self-degradable, polymer-based, temporary diversion materials that are useful in a number of Oil and Gas operations, primarily to facilitate the flow of fluids into areas of the reservoir where they would not normally go based upon fluid dynamics. Fluids that are introduced into a reservoir, for purposes such as stimulation, typically take the path of least resistance and therefore will frequently go into areas where there are open flow paths. These areas of least resistance are not necessarily the areas targeted for stimulation and/or treatment (e.g., to increase production or target formation damage). To counteract this phenomenon of fluid flowing in the path of least resistance, mechanical diversion techniques may be employed. However, a variety of factors, including production need, regulatory requirements, or environmental concerns may necessitate the physical removal of the mechanical diversions. The phenomenon may also be counteracted through the use of temporary degradable diversion systems, for example blocking agents that degrade with time, heat, pressure, or other natural or augmented treatment. These temporary degradable diversions work well for zonal isolation and do not need to be removed (e.g., from a well) mechanically after the intervention since they are capable of degrading (e.g., with time) from a solid polymer state into a fluid, such as a clear non-damaging liquid monomer solution.
The chemistries used for degradable diversions, such as TBLOCKSURE® product chemistries, may be designed to exhibit a variation of jamming, sealing, and degrading properties. For example, diversion agents may be capable of degrading across a wide temperature range to monomer species that will not damage a hydrocarbon bearing formation. In addition, diversion agents may be designed to accommodate significant temperature variations (e.g., from 80° F. up to 325° F.) with variable degradation times (e.g., between a few hours to a few days). This may be achieved, for example, through the selection of polymer chemistry, shape, size, or other particle parameter.
However, despite the useful design of these various degradable polymers, the successful deployment and use of this technology in the field (e.g., as a temporary diverter) is heavily dependent upon optimization that contemplates engineering and geo-mechanical design as it relates to the particulars of the environment. In simpler words, the potential of modern degradable diversion agents is extremely limited in the absence of timely-created workflows and processes that contemplate, in correct proportions, job-specific factors as well as historical field data, experimental data, modeling, and specifically beneficial mathematical analysis.
Furthermore, the effectiveness of diversion application may be expressed as pressure build up in the well and the effectiveness of corresponding stimulation using production data (in an area where the diversion fluids are redirected). However, the efficiency of diverters under downhole condition may not be assessed accurately using these methods in operational environments.